1. Field of the Invention
The present invention relates to a panel device including an input section used for operational input to, for example, an electronic device.
2. Description of the Related Art
Conventionally, in order to allow operation of, for example, an audio device mounted in a car, a switch panel device is installed at a position on the instrument panel where easy operation is available for the driver or passenger. Several switch panel devices are provided with electrostatic capacitive sensors. In a switch panel device of this type, the electrostatic capacitance of an electrostatic capacitive sensor changes when an operator touches a panel section of the switch panel device. By sensing the change, the operation to be carried out is detected.
A connection pattern is formed in the panel section of a switch panel device using such an electrostatic capacitive sensor. The connection pattern electrically connects a detection electrode formed in the panel section to a sensing circuit formed outside the panel section. Therefore, a shield electrode is provided around the connection pattern on the panel section of the panel switch device in order to prevent the electrostatic capacitive sensor from making erroneous detection.
Also in the panel section, an insulating layer is formed between the connection pattern and the shield electrode, in order to prevent the connection pattern and the shield electrode from being electrically connected to each other.
There has been a proposal for use of an insulating sheet member such as resin and the like provided independently from the panel section to form the insulating layer. In this case, the sheet member forming the insulating layer is fixed stacked on the panel section. However, a structure of using the insulating sheet member necessitates an increased number of components and accordingly increases costs. Further, a work process of fixing the sheet member stacked on panel section is required so that costs increases further.
There hence has been also a proposal for forming such an insulating layer by printing. This technique is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-217454.
Meanwhile, there has been also a proposal for forming a connection pattern and a shield electrode by printing an electrically conductive ink on a panel section. However, if a connection pattern and a shield electrode are formed, for example, by printing with use of an electrically conductive ink of a solvent type, a solvent in the connection pattern and the shield electrode positioned in two sides of an insulating layer dissolves the insulating layer, and components such as electrically conductive filler and the like in the connection pattern and the shield electrode enter into the insulating layer.
Since components such as electrically conductive filler in the connection pattern and the shield electrode enters into the insulating layer, insulation of the insulating layer deteriorates. As a result, the connection pattern and the shield electrode are electrically connected to each other through the insulating layer. However, it is undesirable that the connection pattern and the shield electrode are electrically connected to each other.